Electrochemical Properties of Oxide Scale on Steel Exposed in Saturated Calcium Hydroxide Solutions with or without Chlorides

<table class="fixed-width table-group" id="tab7"><tr><td><table class="table"><colgroup><col style="width:7.17em"/><col style="width:5.48em"/><col style="width:4.31em"/><col style="width:4.35em"/><col style="width:5.33em"/><col style="width:4.98em"/></colgroup><tr><td class="thead-hr" colspan="6"><hr/></td></tr><tr class="thead"><td class="align_left">Parameter</td><td class="align_center"> </td><td class="align_center">Steel</td><td class="align_center">Wustite</td><td class="align_center">Magnetite</td><td class="align_center">Hematite</td></tr><tr><td class="thead-hr" colspan="6"><hr/></td></tr><tr><td class="align_left"><span style="width: 50.9697ptpx;"><svg height="12.0621pt" id="M16" style="vertical-align:-3.2957pt" version="1.1" viewbox="-0.0498162 -8.7664 50.9697 12.0621" width="50.9697pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M614 175C564 76 510 21 408 21C256 21 146 149 146 336C146 488 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class="align_center">[<i>μ</i>F.cm<sup>−2</sup>]</td><td class="align_center">53</td><td class="align_center">101</td><td class="align_center">21</td><td class="align_center">21</td></tr><tr><td class="align_left"><span style="width: 55.2285ptpx;"><svg height="11.6836pt" id="M17" style="vertical-align:-3.29562pt" version="1.1" viewbox="-0.0498162 -8.38798 55.2285 11.6836" width="55.2285pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M631 18C609 24 585 35 559 65C534 91 514 117 478 169C448 214 406 281 389 313C462 346 516 399 516 485C516 545 490 590 449 616C412 641 363 650 290 650H42V622C120 615 128 612 128 527V125C128 40 120 34 38 28V0H300V28C221 34 212 40 212 125V284H244C295 284 312 272 329 244C359 195 395 133 430 84C475 19 516 -3 592 -7C603 -8 615 -8 627 -8L631 18ZM212 316V563C212 591 215 602 223 607C231 613 248 617 277 617C352 617 423 577 423 469C423 415 407 375 368 345C343 324 310 316 260 316H212Z" id="g121-80"></path></g><g transform="matrix(.0091,0,0,-0.0091,8.073,3.132)"><path d="M262 451C169 451 38 375 38 210C38 98 121 -12 261 -12C360 -12 481 64 481 227C481 351 386 451 262 451ZM249 414C337 414 385 320 385 204C385 70 333 25 272 25C189 25 134 117 134 241C134 355 189 414 249 414Z" id="g58-109"></path></g><g transform="matrix(.0091,0,0,-0.0091,12.641,3.132)"><path d="M482 0V30C420 38 407 48 370 103L273 248C308 299 331 332 352 357C387 397 401 404 463 409V439H277V409C318 405 324 400 307 369C290 337 270 307 251 279L194 367C175 396 180 402 220 409V439H18V409C74 401 87 395 117 349L204 213C173 168 147 130 119 95C78 46 67 38 5 30V0H195V30C144 38 143 47 162 79C181 112 202 149 225 181L297 70C314 43 307 35 264 30V0H482Z" id="g58-118"></path></g><g transform="matrix(.0091,0,0,-0.0091,17.027,3.132)"><path d="M138 535C169 535 191 560 191 589C191 620 168 644 139 644S85 620 85 589C85 560 110 535 138 535ZM257 0V30C192 35 185 43 185 109V453C142 435 94 422 40 414V386C101 378 104 372 104 311V109C104 41 97 35 33 30V0H257Z" id="g58-103"></path></g><g transform="matrix(.0091,0,0,-0.0091,19.529,3.132)"><path d="M526 56L493 58C457 61 448 68 448 119V710C411 697 344 682 288 675V646C362 641 367 639 367 573V439C344 448 315 451 300 451C164 451 40 342 40 202C40 61 147 -12 227 -12C239 -12 266 -7 305 16L367 53V-12C427 10 505 21 526 26V56ZM367 88C342 69 306 54 271 54C207 54 133 111 133 229C133 373 219 409 264 409C301 409 342 394 367 359V88Z" id="g58-98"></path></g><g transform="matrix(.0091,0,0,-0.0091,24.425,3.132)"><path d="M384 109C349 76 310 59 268 59C197 59 123 113 120 245C240 248 367 259 384 262C403 266 407 275 407 296C407 376 338 451 254 451H253C201 451 148 425 105 378C65 334 39 272 39 203C39 88 112 -12 235 -12C266 -12 339 5 402 84L384 109ZM230 411C285 411 319 365 319 313C319 298 313 293 294 293C236 291 180 290 125 290C141 370 185 411 230 411Z" id="g58-99"></path></g></svg></span></td><td class="align_center">[MΩ.cm<sup>2</sup>]</td><td class="align_center">4<svg height="6.01072pt" id="M18" style="vertical-align:-0.04980993pt" version="1.1" viewbox="-0.0498162 -5.96091 7.75925 6.01072" width="7.75925pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M471 153C471 170 463 194 452 212C400 220 373 229 322 255C373 281 400 290 452 298C463 316 471 339 471 357C456 366 431 371 410 370C377 329 356 310 308 279C311 336 317 364 336 413C326 432 310 451 294 459C279 451 262 432 252 413C271 364 277 336 280 279C232 310 211 329 178 370C157 371 132 367 117 357C117 340 125 316 136 298C188 290 215 281 266 255C215 229 188 220 136 212C125 194 117 171 117 153C132 144 157 139 178 140C211 181 232 200 280 231C277 174 271 146 252 97C262 78 278 59 294 51C309 59 326 78 336 97C317 146 311 174 308 231C356 200 377 181 410 140C431 139 456 143 471 153Z" id="g113-43"></path></g></svg>10<sup>−11</sup></td><td class="align_center">0.002</td><td class="align_center">0.002</td><td class="align_center">0.01</td></tr><tr><td class="align_left"><span style="width: 61.8547ptpx;"><svg height="11.9479pt" id="M19" style="vertical-align:-3.181499pt" version="1.1" viewbox="-0.0498162 -8.7664 61.8547 11.9479" width="61.8547pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M614 175C564 76 510 21 408 21C256 21 146 149 146 336C146 488 235 629 402 629C510 629 570 586 597 480L626 488C620 541 614 582 606 638C578 643 510 665 429 665C206 665 44 527 44 316C44 157 153 -15 402 -15C474 -15 558 5 586 11C604 45 629 119 643 165L614 175Z" id="g121-65"></path></g><g transform="matrix(.013,0,0,-0.013,8.645,0)"><path d="M46 650V622C120 617 128 613 128 525V125C128 42 120 34 40 28V0H311V28C221 34 212 39 212 124V281L286 262C297 261 316 261 331 263C429 275 526 338 526 468C526 533 501 579 462 609C422 638 364 650 293 650H46ZM212 559C212 588 215 600 223 606C230 613 251 618 279 618C361 618 430 572 430 464C430 337 350 302 285 302C252 302 225 309 212 314V559Z" id="g121-78"></path></g><g transform="matrix(.013,0,0,-0.013,15.899,0)"><path d="M517 162C503 123 484 88 467 68C445 42 417 34 341 34C291 34 256 34 237 47C219 59 213 81 213 128V317H308C395 317 402 311 415 240H444V431H415C403 364 398 356 307 356H213V584C213 613 215 616 246 616H322C394 616 421 609 435 587C448 566 458 544 467 502L496 506C493 557 488 625 488 650H42V622C120 616 128 612 128 523V125C128 43 120 35 29 28V0H511C520 31 540 125 546 158L517 162Z" id="g121-67"></path></g><g transform="matrix(.0091,0,0,-0.0091,23.37,3.132)"><path d="M43 650V617C122 612 130 606 130 522V128C130 44 122 37 34 32V0H275C400 0 497 25 573 82C652 142 698 229 698 350C698 445 662 518 613 565C549 625 456 650 327 650H43ZM217 544C217 580 220 591 229 599C240 607 264 613 311 613C380 613 437 599 482 570C561 523 598 436 598 336C598 177 511 40 324 40C248 40 217 61 217 135V544Z" id="g58-66"></path></g><g transform="matrix(.0091,0,0,-0.0091,30.077,3.132)"><path d="M499 166C484 119 466 88 447 68C424 43 390 38 338 38C297 38 262 40 242 51C223 62 218 80 218 133V522C218 607 226 612 309 617V650H41V617C124 612 131 605 131 522V129C131 45 123 38 38 33V0H497C505 30 529 128 534 160L499 166Z" id="g58-74"></path></g></svg></span></td><td class="align_center">[<i>μ</i>F.cm<sup>−2</sup>]</td><td class="align_center">15</td><td class="align_center">130</td><td class="align_center">11</td><td class="align_center">17</td></tr><tr><td class="align_left"><span style="width: 77.0953ptpx;"><svg height="11.5695pt" id="M20" style="vertical-align:-3.18152pt" version="1.1" viewbox="-0.0498162 -8.38798 77.0953 11.5695" width="77.0953pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M631 18C609 24 585 35 559 65C534 91 514 117 478 169C448 214 406 281 389 313C462 346 516 399 516 485C516 545 490 590 449 616C412 641 363 650 290 650H42V622C120 615 128 612 128 527V125C128 40 120 34 38 28V0H300V28C221 34 212 40 212 125V284H244C295 284 312 272 329 244C359 195 395 133 430 84C475 19 516 -3 592 -7C603 -8 615 -8 627 -8L631 18ZM212 316V563C212 591 215 602 223 607C231 613 248 617 277 617C352 617 423 577 423 469C423 415 407 375 368 345C343 324 310 316 260 316H212Z" id="g121-80"></path></g><g transform="matrix(.0091,0,0,-0.0091,8.073,3.132)"><path d="M43 650V617C122 612 130 606 130 522V128C130 44 122 37 34 32V0H275C400 0 497 25 573 82C652 142 698 229 698 350C698 445 662 518 613 565C549 625 456 650 327 650H43ZM217 544C217 580 220 591 229 599C240 607 264 613 311 613C380 613 437 599 482 570C561 523 598 436 598 336C598 177 511 40 324 40C248 40 217 61 217 135V544Z" id="g58-66"></path></g><g transform="matrix(.0091,0,0,-0.0091,14.78,3.132)"><path d="M499 166C484 119 466 88 447 68C424 43 390 38 338 38C297 38 262 40 242 51C223 62 218 80 218 133V522C218 607 226 612 309 617V650H41V617C124 612 131 605 131 522V129C131 45 123 38 38 33V0H497C505 30 529 128 534 160L499 166Z" id="g58-74"></path></g></svg></span></td><td class="align_center">[MΩ.cm<sup>2</sup>]</td><td class="align_center">0.012</td><td class="align_center">0.25</td><td class="align_center">2</td><td class="align_center">124</td></tr><tr class="table-tr"><td colspan="6"><hr class="tbody-hr"/></td></tr></table></td></tr></table>

<div>Parameter data obtained from the equivalent circuit fitting for samples exposed in sat. Ca(OH)<sub>2</sub> with 0.6 M Cl<sup>-</sup>. The data values are an average of two samples.</div>

International Journal of Corrosion

tab7

Table 7

Table 7: Electrochemical Properties of Oxide Scale on Steel Exposed in Saturated Calcium Hydroxide Solutions with or without Chlorides 